Method of bonding ferrous and nonferrous metals



H. E. DEPUTY Original Filed Dec. 26, 1955 INVEIiT/TOR v f 7 flan" RNEYS.

Jforac 8 BY QL July 12, 1938.

METHOD OF BONDING FERROUS AND NONFERROUS METALS Patented? July 12, 1938PATENT OFFICE.

METHOD OF BONDING FERROUS AND NON- FERROUS METALS Horace E. Deputy,Rochester, Minn.

Application December 26, 1935, Serial No. 56,132 Renewed September "I,1937 3 Claims.

This invention relates to methods of bonding ferrous and non-ferrousmetals, and more particularly to an improved process whereby a molecularbond and absolute union may be secured 5 between aluminum, or analuminum alloy, and iron or steel. While the invention is illustrated asapplied to securing together a steel reinforcing sleeve and the body ofan aluminum alloy piston, many other applications will be readilyunderstood to exist. An important object of the invention, in additionto that inhering in the provision of such bonding process, resides inthe provision of such an improved piston construction the ferrous andnon-ferrous parts of which are so united, to form a rigid unit, thatthey cannot be loosened or separated, by subjection thereof to eitherphysical abuse or Wide changes of temperature.

Other objects and advantages will be apparent from the followingdescription wherein reference is made to the accompanying drawingillustrating a preferred embodiment of my invention and wherein similarreference numerals designate similar parts throughout the several 25views.

In the drawing The single figure represents in diametric cross section atrunk-type piston incorporating the principles of the invention.

Referring now to the drawing, and to the process in greater detail; theinside surface of the steel sleeve, as H], (or other ferrous surfacewith which the aluminum or aluminum alloy is to be bonded) may be leftin unfinished condition, since the aluminum is poured, while molten,into engagement therewith, and takes the configuration of the ferroussurface. The exterior of the sleeve is of course machined or ground tothe desired diameter, and its edges may be beveled, as at H, in orderthat they may project beneath a portion of the aluminum alloy pistonbody (l2), after the parts are cast together, to provide a. mechanicallock in the form of a dovetail joint. The sleeve is heated toapproximately 850 degrees F., and then dipped in a bath of molten zinc,preferably of the variety sold commercially as Western Spelter, suchbath being held at approximately 830 degrees F. The sleeve may or maynot thereafter be allowed to cool, as desired, but in either event it isPreferably predegrees R, such preheating being. effected in anon-oxidizing oven to prevent oxidation of the zinc.

A permanent mold (unshown) is employed, the

heated before insertion in the mold, to about 860 mold being preheatedto approximately the same temperature as the iron or steel sleeve (860degrees F.) and the molten aluminum alloy p ured. thereinto at atemperature of from 1280 to 1360 degrees F., depending upon itscomposition, after the sleeve is positioned in the mold.

A suitable alloy for pistons, and one which bonds exceedingly well,comprises Parts so bonded, and of physical proportions suitable for use,for example, in automobile engines, bond perfectly and cool sufficientlyin from one to one and one- -half minutes, although the cooling timemust of course be somewhat increased if the work be more massive. Thenonferrous metal should be poured without allowing the sleeve to remainheated in normal or oxygencontaining atmosphere for a longer period thanis necessary, in order that undue oxidation of the coated sleeve may beprevented.

I have found it to be important to employ a' non-oxidizing or reducingoven in preheating the zinc-coated steel or iron, and such preheating isan important operation if reliable and uniform bonding is to be secured.

The Western Spelter employed contains as impurities approximately Pb1.60 Fe .08 Cd A trace Although it has not been determined that the lastelement is necessary, equivalent results cannot be secured with purezinc.

What I claim is:

1. The process of bonding a ferrous metal with a non-ferrousmetalcomprising at least partly aluminum, which comprises heating the ferrousmetal'to approximately 850 degrees F., dipping the ferrous metal in amolten bath comprising principally zinc but including small quantitiesof iron and lead, to coat the ferrous metal therewith, the bath being ata temperature of approximately 860degrees F. while limiting access ofoxygen thereto, and quickly thereafter pouring the non-ferrous metalinto engagement with the coated surface of the ferrous metal.

2. The process of bonding ferrous metal with a non-ferrous metalcomprising at least partly aluminum, which comprises heating the ferrousmetal to approximately 850 degrees 1",, coating the ferrous metal with ametal comprising principally zinc but including .a small quantity oflead, heating the coated ferrous metal to a temperature of approximately830 degrees F. while limiting access of oxygen to the coated surface,and quickly thereafter pouring the non-ferrous metal in molten conditioninto engagement with the ferrous metal.

8. The process 'of forming a'composite piston same temperature, andpouring the non-ferrous metal into the mold and sleeve to cast and bondsuch metal to the sleeve.

HORACE n. DEPUTY,

